update docs

Author: cpanato

.gitignore

@@ -1,5 +1,6 @@
 github_actions_exporter
 *.env
+*.tar.gz
 
 # Binaries for programs and plugins
 *.exe

.promu.yml

@@ -1,6 +1,4 @@
 go:
-    # Whenever the Go version is updated here,
-    # .circle/config.yml should also be updated.
     version: 1.15
 repository:
     path: github.com/cpanato/github_actions_exporter
@@ -14,3 +12,9 @@ build:
 tarball:
     files:
         - LICENSE
+crossbuild:
+    platforms:
+        - linux/amd64
+        - darwin/amd64
+        - windows/amd64
+        - linux/arm64

README.md

@@ -42,6 +42,17 @@ make build
 ./github_actions_exporter --gh.github-webhook-token=MY_TOKEN
 ```
 
+## Docker
+
+You can deploy this exporter using the [ghcr.io/cpanato/github_actions_exporter-linux-amd64](https://github.com/users/cpanato/packages/container/package/github_actions_exporter-linux-amd64) Docker image.
+
+For example:
+
+```bash
+docker pull ghcr.io/cpanato/github_actions_exporter-linux-amd64:v0.1.0
+docker run -d -p 9101:9101 ghcr.io/cpanato/github_actions_exporter-linux-amd64:v0.1.0 --gh.github-webhook-token="1234567890token"
+```
+
 ## Testing
 
 ### Running unit tests